Background Disseminated herpes zoster infection occurs mostly in immunocompromised hosts. There have been recent reports of disseminated zoster with chemotherapeutic regimens and newer monoclonal antibodies. Case report The present case describes a 61‐year‐old patient presenting with disseminated herpes zoster after initiation of benralizumab, an anti‐IL‐5 monoclonal antibody for severe persistent asthma. His initial vesicular lesions limited to left lumbar dermatomes progressed extensively resulting in dissemination on his body. The diagnosis was confirmed with PCR and he had remarkable clinical improvement with acyclovir and supportive medical management. Conclusion Clinical trials have reported an association of mepolizumab, another anti‐IL‐5 monoclonal antibody with herpes zoster. This report of herpes zoster following initiation of benralizumab might suggest a possibility of a class effect of anti‐IL‐5 monoclonal antibody.